That’s because the drive was written to its limits; the defrag runs a TRIM command that safely releases and resets empty sectors. Random reads and sequential reads /on clean drives that are regularly TRIMmed/ are within random variance of each other.
Source: ran large scale data collection for a data centre when SSDs were relatively new to the company so focused a lot on it, plus lots of data from various sectors since.
According to the man(8) page, it will avoid touching any blocks that have the chattr -f flag set, which is XSR_XFLAGS_NODEFRAG… So I think if the docs are still accurate to the code, yes.
That’s because the drive was written to its limits; the defrag runs a TRIM command that safely releases and resets empty sectors. Random reads and sequential reads /on clean drives that are regularly TRIMmed/ are within random variance of each other.
Source: ran large scale data collection for a data centre when SSDs were relatively new to the company so focused a lot on it, plus lots of data from various sectors since.
I’m pretty sure running XFS defrag will defrag without trimming no matter the type of block device.
I understood that XFS automatically mounted SSD’s with XFS_XFLAG_NODEFRAG set? Is this not the case?
yea you might actually be right. I Played with my fstab too much years ago, and never thought of that until now
But does that flag affect manually running xfs_fsr?
According to the man(8) page, it will avoid touching any blocks that have the
chattr -fflag set, which is XSR_XFLAGS_NODEFRAG… So I think if the docs are still accurate to the code, yes.A lot of ifs in that assumption.